AMD is suing four former managers for intellectual property theft, claiming that they set up a spying ring within the company before jumping ship and joining its rival, Nvidia.

"This is an extraordinary case of trade secret transfer/misappropriation and strategic employee solicitation," reads AMD's court filing in Massachusetts district court on Monday.

"Thousands of AMD document or electronic files have been taken from its facilities by employees leaving to work for a primary competitor in the graphics business Nvidia Corporation."

The suit alleges that Robert Feldstein, an AMD manager who left the firm in July 2012, used two external hard drives to download licensing agreements and strategic plans from his work computer, as well as copies of his Outlook email files.

He also recruited a colleague, Richard Hagen, to the plan, and together they found two more employees willing to move and bring secrets with them, the lawsuit claims.

AMD staffer Manoo Desal brought over a 200-file database of AMD's technological work and development from its Perforce file management system, and Nicolas Kociuk copied over 150,000 files in the two weeks before his resignation, the chip designer's legal team claims. AMD is still trying to determine if others were involved in the scheme.

AMD is no stranger to cases of this type, although last time the boot was on the other foot. Former Intel employee Biswamohan Pani pleaded guilty to taking Itanium roadmap documents with him when he joined the competition at AMD, although the court found he did it without his new employer's knowledge. ®